The other responses have this right. I think the Redux pattern is similar enough to Elm that I didn't feel a need to make a finer distinction.
I'll also say this: the tools that Rust provides for reasoning about mutation are powerful and principled. A central philosophy of Rust is that mutation isn't the problem, it's shared mutable state. If you believe that philosophy (and I do), then restricting yourself to pure functions over clonable state feels like tying one hand behind your back. I hope I've made the case that providing finer grained access to mutable app state is an approach at least worth exploring.
I'll also say this: the tools that Rust provides for reasoning about mutation are powerful and principled. A central philosophy of Rust is that mutation isn't the problem, it's shared mutable state. If you believe that philosophy (and I do), then restricting yourself to pure functions over clonable state feels like tying one hand behind your back. I hope I've made the case that providing finer grained access to mutable app state is an approach at least worth exploring.